Research Projects

In the project “EmitterPlus”, gas phase emitters (RVD: rapid vapor-phase direct doping) are investigated as an alternative to conventional emitters in solar cells with selective contacts (TOPCon: tunnel oxide passivated contacts). The aim is to develop an integrated process for emitter diffusion and annealing of the selective contacts, with which solar cells can be produced with an efficiency of 25%. For this purpose, existing processes will be adapted and further developed. In addition to the demonstration of highly efficient solar cells, the process and machine know-how necessary for an industrial implementation of the gas phase emitter process will be generated in order to subsequently develop the industrial implementation together with machine builders. | Duration: 06/2018 - 05/2020

Due to ongoing improvements in material quality and surface passivation, recombination at the metal contacts has become one of the dominant loss mechanisms in silicon solar cells. This loss can be reduced by usingso-called passivated contacts, which suppress the recombination of minority charge carriers and simultaneously allow lossless majority charge carrier transport. On the basis of an extremely thin dielectric tunnel oxide, we have succeeded in producing a very effective, passivated contact (TOPCon), which simultaneously passivates the surface excellently and constitutes low resistance to charge carrier transport. | Duration: 07/2011 - 06/2015

Perovskite-silicon tandem solar cells enable higher efficiency levels than today’s silicon solar modules, but place high demands on module manufacturing. HoTSun is developing gentle processes to reliably interconnect and encapsulate these sensitive cells and process them into industrial-grade PV modules with an efficiency of over 26 percent. | Duration: 03/2025 - 02/2027

Project in the Business Area: Photovoltaics, Topic: Silicon Photovoltaics, Perovskite and Organic Photovoltaics; Field of Work: Perovskite Silicon Tandem Photovoltaics, High-Efficiency Silicon Cell Fabrication and Analysis; Duration: 02/2021 - 01/2024

In order to produce perovskite layers of the highest quality for perovskite-silicon tandem solar cells, we are pursuing a hybrid route combining vacuum evaporation and solution deposition. The two processes complement each other perfectly to enable the deposition of perovskite layers on micrometer-sized silicon pyramids. This has enabled us to achieve efficiencies of over 32%. We are now transferring this technology to our Pero-Si-SCALE technology platform using industrially scalable equipment for full wafer sizes (M12). | Laufzeit: 05/2023 - 04/2026

The interconnection and module integration of perovskite silicon tandem solar cells based on Qcells' Q.ANTUM technology is to be brought to a higher TRL in preparation for future industrialization. The project aims to develop novel, innovative methods, including low-temperature soldering, conductive bonding and low-temperature lamination for glass-glass modules. In addition, lead-free cell interconnection contributes to the reduction of the harmful substance, which in turn contributes to the development of a sustainable product and the simplification of recycling. Finally, cost savings, increased efficiency and the development of highly efficient high-throughput concepts for industrial production will be investigated. | Duration: 09/2022 - 10/2025

Tandem photovoltaics is one of the fastest developing fields of solar research today. In industry today, single-junction silicon solar cells are the state of the art. At Fraunhofer ISE, it has already been demonstrated that using layers of III-V compound semiconductors the Auger limit of silicon, which is 29.4% efficiency, can be surpassed. The most recent record is 36.1% (2023). The task now is to make the manufacturing processes required to produce these III-V//Si tandem solar cells more cost-effective and efficient and to scale them up further. The first goal of small series production is to realize a module prototype with an efficiency of more than 30%. | Duration: 01/2023 - 12/2025

Project in the Business Area Photovoltaics, Topic: III-V and Concentrator Photovoltaics, Silicon Photovoltaics Fields of Work: III-V Epitaxy and Solar Cells, High-Efficiency Cell Fabrication and Analysis, Metallization and Patterning Duration: May 2015 - April 2019

Perovskite solar cells promise maximum efficiency. However, large-scale industrial production has so far failed due to the complexity of the spraying process. A reproducible, scalable process is intended to remedy this situation for the industry. In the “INTERVENTION” project, we investigated the optimization of spray coating by means of digital simulation of the process and experimental characterization of the materials. A research team developed data-driven solutions for systematic parameter optimization. The aim of the project was to achieve more efficient production on large wafer formats and faster optimization without time-consuming test series – a decisive step towards economically viable high-performance solar cells. | Duration: 01/2023 - 10/2025

Project in the Business Area Photovoltaics; Topics: Silicon Photovoltaics, III-V- and Concentrator Photovoltaics and Emerging Photovoltaic Technologies; Fields of Work: High-Efficiency Cell Fabrication and Analysis, III-V Epitaxy and Solar Cells, Photon Management; Duration: April 2013 - March 2015